Reassigning Source Peers

1. A system for delivering assignment information over a distribution network comprising a plurality of peers organized in a content distribution topology, the system comprising a distribution manager, including: a processor; and a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to: send a first assignment of a first set of one or more source peers in the plurality of peers in the distribution network to provide audiovisual content to a destination peer in the plurality of peers in the distribution network; detect at least one of a change in a network condition and a policy change associated with another peer in the distribution network that is different from the destination peer; determine, based at least in part on the detected at least one change and one or more thresholds, that at least a portion of the content distribution topology should be recalculated; in response to the determination that the at least portion of the content distribution topology should be recalculated, recalculate the at least portion of the content distribution topology, wherein recalculating the content distribution topology includes reassessing peers used to exchange audiovisual content, and wherein the recalculation is based at least in part on an evaluation of uplink capacities of at least some of the peers used to exchange audiovisual content; determine, based at least in part on the recalculated at least portion of the content distribution topology, that the first assignment sent to the destination peer should be modified; and in response to the determination that the first assignment sent to the destination peer should be modified: generate, according to the recalculated content distribution topology, a revised assignment of a second set of one or more source peers in the distribution network that is different from the first set of one or more source peers; and propagate the revised assignment to the destination peer, wherein the propagated revised assignment causes the destination peer to request content from the second set of one or more source peers.

2. The system of claim 1 wherein the recalculation is based at least in part on at least one new peer joining the distribution network.

3. The system of claim 2 wherein the new peer has a higher priority than the destination peer.

4. The system of claim 1 wherein the recalculation is based at least in part on at least one existing peer leaving the distribution network.

5. The system of claim 1 wherein the recalculation is based at least in part on a detected network failure.

6. The system of claim 1 wherein the recalculation is based at least in part on a detection of network congestion.

7. The system of claim 1 wherein the recalculation is based at least in part on the computation of an objective function.

8. The system of claim 1 wherein the recalculation is based at least in part on a detected violation of a content delivery policy.

9. The system of claim 8 wherein the content delivery policy is a network policy.

10. The system of claim 8 wherein the content delivery policy is a provider policy.

11. The system of claim 8 wherein the content delivery policy is a client policy.

12. The system of claim 1 wherein the recalculation is based at least in part on an evaluation of geographic proximity of the at least some of the peers used to exchange content.

13. A method of delivering assignment information over a distribution network comprising a plurality of peers organized in a content distribution topology using a distribution manager, including: sending, by the distribution manager, a first assignment of a first set of one or more source peers in the plurality of peers in the distribution network to provide audiovisual content to a destination peer in the plurality of peers in the distribution network; detecting, by the distribution manager, at least one of a change in a network condition and a policy change associated with another peer in the distribution network that is different from the destination peer; determining, by the distribution manager and based at least in part on the detected at least one change and one or more thresholds, that at least a portion of the content distribution topology should be recalculated; in response to the determination that the at least portion of the content distribution topology should be recalculated, recalculating, by the distribution manager, the at least portion of the content distribution topology, wherein recalculating the content distribution topology includes reassessing peers used to exchange audiovisual content, and wherein the recalculation is based at least in part on an evaluation of uplink capacities of at least some of the peers used to exchange audiovisual content; determining, by the distribution manager and based at least in part on the recalculated at least portion of the content distribution topology, that the first assignment sent to the destination peer should be modified; and in response to the determination that the first assignment sent to the destination peer should be modified: generating, by the distribution manager and according to the recalculated content distribution topology, a revised assignment of a second set of one or more source peers in the distribution network that is different from the first set of one or more source peers; and propagating, by the distribution manager, the revised assignment to the destination peer, wherein the propagated revised assignment causes the destination peer to request content from the second set of one or more source peers.

14. The method of claim 13 wherein the recalculation is based at least in part on at least one new peer joining the distribution network.

15. The method of claim 14 wherein the new peer has a higher priority than the destination peer.

16. The method of claim 13 wherein the recalculation is based at least in part on at least one existing peer leaving the distribution network.

17. The method of claim 13 wherein the recalculation is based at least in part on a detected network failure.

18. The method of claim 13 wherein the recalculation is based at least in part on a detection of network congestion.

19. The method of claim 13 wherein the recalculation is based at least in part on the computation of an objective function.

20. The method of claim 13 wherein the recalculation is based at least in part on a detected violation of a content delivery policy.

21. A computer program product for delivering assignment information over a distribution network comprising a plurality of peers organized in a content distribution topology using a distribution manager, the computer program product being embodied in a non-transitory computer readable medium and comprising computer instructions for: sending, by the distribution manager, a first assignment of a first set of one or more source peers in the plurality of peers in the distribution network to provide audiovisual content to a destination peer in the plurality of peers in the distribution network; detecting, by the distribution manager, at least one of a change in a network condition and a policy change associated with another peer in the distribution network that is different from the destination peer; determining, by the distribution manager and based at least in part on the detected at least one change and one or more thresholds, that at least a portion of the content distribution topology should be recalculated; in response to the determination that the at least portion of the content distribution topology should be recalculated, recalculating, by the distribution manager, the at least portion of the content distribution topology, wherein recalculating the content distribution topology includes reassessing peers used to exchange audiovisual content, and wherein the recalculation is based at least in part on an evaluation of uplink capacities of at least some of the peers used to exchange audiovisual content; determining, by the distribution manager and based at least in part on the recalculated at least portion of the content distribution topology, that the first assignment sent to the destination peer should be modified; and in response to the determination that the first assignment sent to the destination peer should be modified: generating, by the distribution manager and according to the recalculated content distribution topology, a revised assignment of a second set of one or more source peers in the distribution network that is different from the first set of one or more source peers; and propagating, by the distribution manager, the revised assignment to the destination peer, wherein the propagated revised assignment causes the destination peer to request content from the second set of one or more source peers.